Some will point the finger of blame at head coach Sir Clive Woodward after the All Blacks posted three emphatic Test match victories - 21-3, 48-18 and 38-19.
But O'Connell believes Woodward's playing squad must take its share of the flak.
Woodward took a record 45-man group to New Zealand, which rose to 50 when Simon Shaw, Simon Easterby, Ryan Jones, Brent Cockbain and Jason White joined the trip as tour replacements.
But their combined expertise, complete with a 29-strong backroom team, flew home on Sunday knowing some will tag them as failures.
"I think we have to take collective responsibility," said Irish lock O'Connell, who was among a handful of players to start all three Tests.
"There were mistakes made but at the same time I think Clive needed players to produce the goods, and myself and other guys haven't done that. It needs to go both ways.
"Maybe you can point the finger at the coaching staff but we are all experienced international players and not one of us can hold our hands up and say we've had very good tours.
"The All Blacks were very good but we were nowhere near."
O'Connell added: "When you look back at the 1997 Lions tour to South Africa, there were a lot of stand-out guys, people like Scott Gibbs, Paul Wallace, Matt Dawson, Gregor Townsend and Lawrence Dallaglio. We had no real stand-out players.
"A lot of us just didn't bring our A-games with us. In the last two Tests, I've never spilled as much ball in my life.
"'Drisco' (Brian O'Driscoll) went in the first Test, and we just had no real inspirational stand-out players to feed off and it killed us."
O'Connell confirmed the popular theory that preparing a squad in just six weeks for as tough a challenge as the All Blacks presented a huge degree of difficulty.
"In the old days, when defence wasn't as structured, the lineout wasn't as structured as it is now and attack wasn't as structured, then six weeks was okay to get a team together," said the Munster forward.
"As this level, with the game so professional and everything so rehearsed, six weeks to put in a defensive structure, an attacking structure and a lineout structure is very tough.
"You've got to have everything right and then you can start to play hard rugby and play continuity rugby, but I suppose we were trying to play hard rugby and find our feet at the same time.
"I have never been on a Lions tour before, so I've never experienced it, but it has been a really hard one to put together.
"Enjoyment comes from winning and we haven't been winning. We are all very competitive, professional sportsmen, and when you lose, for the rest of the week you end up torturing yourself.
"Things could have been done differently but hindsight is a wonderful thing. When we set out, we were totally in agreement with what we were doing. We were all perfectly happy with the way things were being run."
Fly-half Stephen Jones identified the contact area as a zone where the Lions found life particularly testing.
"It was very physical here, and against every team we played, every contact area was a war zone," he said.
"We had to become efficient in that area, and it took us a while to do that.
"You have to give New Zealand credit because every contact was ferocious and they were very efficient. As soon as the ball was won, they would play with a lot of width as well, so they moved the ball around and played with a lot of tempo.
"We were given everything to succeed on this trip. I look back, and you feel a little bit frustrated with the rugby because I don't feel we have done ourselves justice.
"From the rugby side of things, your weaknesses tend to get magnified in New Zealand, and I know from a personal point of view, there are many areas of my game that I have to start working on now."